Gas dispersion system

Abstract

A gas dispersion system for dispersing noxious gas released into the atmosphere within a contained ground area to prevent its passing at an unacceptable concentration to a neighboring ground area to be protected, comprising means responsive to the release of gas within the contained area for producing a trip signal, air heating means extending along a base region interposed between the contained area and the protected area, the air heating means being operable to produce an upward flow of heated air from the base region to form a buoyant plume of rising air for dispersing the gas upwards, and control means responsive to said trip signal for initiating operation of the air heating means.

What we claim is: 
     
       1. In combination with a gas dispersion system for dispersing noxious gas released into the atmosphere within a contained ground area to prevent its passing at an unacceptable concentration to a neighbouring ground area to be protected, the system comprising a plurality of gas sensors distributed along a first base region, the gas sensors being positioned and arranged to intercept the flow of gas from the contained area towards the protected area,   circuit means coupled to the gas sensors for producing a trip signal in accordance with the detection of gas thereby,   a plurality of burners distributed along a second base region interposed between the first base region and the protected area, the burners being so positioned and arranged so that, when ignited, they produce by thermal convection an air curtain for dispersing the gas upwards,   control means responsive to said trip signal,   fuel supply means for the burners, and   ignition means operable by the control means in response to said trip signal for igniting the burners thereby to produce the air curtain,   display means comprising a console display panel and condition-responsive means for producing thereon a display representative of the current condition of the system, the display panel providing a ground plan of the plant, a first set of indicator lamps located at positions on the panel corresponding to the positions of the gas sensors, a second set of indicator lamps located at positions on the panel corresponding to the positions of the burners, and wind direction and velocity indicating means, said condition-responsive means including means responsive to ignition of the burners for illuminating the second set of indicator lamps, and means responsive to said warning signals for illuminating the first set of indicator lamps selectively in accordance with the detection of gas by the corresponding gas sensors of the corresponding groups.   
     
     
       2. A gas dispersion system according to claim 1, wherein the first and second base regions wholly surround the contained area, the first base region being wholly surrounded by the second base region. 
     
     
       3. A gas dispersion system according to claim 1, wherein the gas sensors are mounted on support towers spaced along said first base region, each tower carrying a plurality of gas sensors mounted at different heights. 
     
     
       4. A gas dispersion system for use in association with an industrial plant in which a noxious gas is normally contained under pressure, the system being operable to disperse such gas which may be accidentally released into the atmosphere, so as to prevent its passing at an unacceptable concentration to a neighbouring area to be protected, the system comprising: pressure monitoring means for monitoring the pressure of the contained gas,   circuit means responsive to said pressure monitoring means for producing a first trip signal in accordance with a fall of pressure of the contained gas in excess of a predetermined rate,   a plurality of gas sensors wholly surrounding an area of the plant in which the gas is normally contained, the sensors being positioned and arranged to inercept the flow of gas from the contained area towards the protected area,   circuit means responsive to said gas sensors for producing a second trip signal in accordance with the detection of gas thereby at a concentration higher than a predetermined level,   a plurality of burners distributed along a base region surrounding the gas sensors, the burners being so positioned and arranged that, when ignited, they produce by thermal convection an air curtain for dispersing the gas upwards,   control means responsive to said first and second trip signals,   fuel supply means for the burners, and   ignition means operable by the control means in response to said first or second trip signal for igniting the burners thereby to produce the air curtain.   
     
     
       5. A gas dispersion system according to claim 4, wherein the gas sensors are interconnected in groups, the sensors of each group being distributed along a common segment of the periphery of said area of the plant in which the gas is normally contained, each group of sensors being connected to a respective one of a plurality of warning circuits, each warning circuit being operable to produce a warning signal in response to the detection of gas by the sensors of its associated group at a concentration below said predetermined concentration. 
     
     
       6. In combination with a gas dispersion system according to claim 5, a console display panel and condition-responsive means for producing thereon a display representative of the current condition of the system, the display panel providing a ground plan of the plant, a first set of indicator lamps located at positions on the panel corresponding to the positions of the gas sensors, a second set of indicator lamps located at positions on the panel corresponding to the positions of the burners, and wind direction and velocity indicating means, said condition-responsive means including means responsive to ignition of the burners for illuminating the second set of indicator lamps, and means responsive to said warning signals for illuminating the first set of indicator lamps selectively in groups in accordance with the detection of gas by gas sensors of the corresponding groups.